1. Field of the Invention
This invention relates to photographic materials comprising oxoindolizine and oxoindolizinium dye images. It also relates to the formation of such dye images in photographic materials.
2. Description of the State of the Art
Formation of image dyes in photographic materials is well known in the photographic art. However, a continuing need has existed for new classes of image dyes which are capable of a range of absorption and are formed in a photographic material without the need for complex multistep reactions.
Preparation of images without the need for silver, such as without the need for photographic silver halide, is known in the photographic art. The use of photosensitive cyclopropenones for forming vesicular images has been described as one form of such imaging. This is described in, for example U.S. Pat. Nos. 4,106,938 and 4,128,422. It has been desirable to provide a photographic material that enables formation of new image dyes that have a wide range of absorption by means of photosensitive cyclopropenones.